Cleansing compositions are used to apply to the hair and/or skin of humans in order to provide cleansing of the respective part of the body to be cleaned. With respect to cleansing skin, cleansing formulations are designed to remove dirt, sweat, sebum, and oils from the skin, where cleansing is achieved through the use of conventional surfactants that aid in the uplifting of dirt and solubilization and removal of oily soils from the skin. In addition to removing unwanted materials from the skin, cleansing helps to promote normal exfoliation, and thereby rejuvenates the skin. Conventional detergents, such as cationic, anionic and non-ionic surfactants, are widely used in a variety of cleansing compositions to impart such cleansing properties.
Also, certain zwitterionic surfactants, like betaines, sultaines and amphoacetates, are widely used in a variety of cleansing compositions. They are best known to generate desirable viscosity, foam and mildness in cleansing formulations, the most commonly used being cocamidopropyl betaine. Other examples include lauramidopropyl betaine, cocamidopropyl hydroxysultaine, lauramidopropyl hydroxysultaine, sodium lauroamphoacetate, sodium cocoamphoacetate, disodium cocoamphodipropionate and disodium lauroamphodipropionate, and the like. However, these zwitterionic surfactants all bear an alkylamidoamine moiety and recently have been recognized as possible allergens. In particular, cocamidopropyl betaine is now part of skin allergy screening tests. Further, allergens and skin irritants such as alkylamidoamines and aminoalkylamines are present as impurities in all of the zwitterionic surfactants noted above, the former an intermediate formed during the synthesis of the above zwitterionic surfactants and the latter an unreacted raw material used for the synthesis.
Applicants have recognized the desirability of developing cleansers that are substantially free of zwitterionic surfactants derived from alkylamidoamines and free of alkylamidoamine and aminoalkylamine impurities, while still fulfilling the demand for desirable viscosity, foam and mildness.
Zwitterionic surfactants are best suited to help generate desirable viscosity, foam and mildness in cleansing formulations. Accordingly, applicants have recognized the need to develop cleansing compositions containing zwitterionic surfactants which do not contain an amidoamine moiety and that are substantially free of alkylamidoamines and aminoalkylamine impurities, and that exhibit desirable viscosity, foam and mildness for consumer use.